The subject invention relates to a recliner assembly for pivotally adjusting a seat back relative to a seat cushion of an automotive vehicle seat.
Automotive vehicles include seat assemblies for supporting a seated occupant in the vehicle. The seat assemblies typically comprise a seat cushion and a seat back pivotally connected to the seat cushion by a recliner mechanism allowing adjustment of the seat back relative to the seat cushion between a plurality of reclined positions. Each of the seat cushion and seat back commonly comprise a rigid frame structure supporting a cellular foam pad that is encased by a fabric trim cover.
Continuously engaged disc recliners are well known in the vehicle seating art and are commonly used to pivotally connect the seat back to the seat cushion. Continuously engaged disc recliners commonly include a cylindrical inner disc fixedly secured to the seat cushion and a cylindrical outer disc fixedly secured to the seat back and rotatably coupled to the inner disc. Continuously engaged disc recliners further include a locking mechanism for maintaining the angular position of the seat back relative to the seat cushion. The locking mechanism typically includes an annular rim on the outer disc having a plurality of first gear teeth and an annular rim on the inner disc having a plurality of second gear teeth. The inner disc has at least one less gear tooth than the outer disc. The first gear teeth of the outer disc are held in continuous meshing engagement with the second gear teeth of the inner disc by an eccentric input shaft rotatably journaled to the outer and inner discs. The angular position of the seat back is adjusted by rotating the input shaft. Rotation of the input shaft drives the outer disc and the seat back in a hypocycloidal motion as the outer disc moves around the annular rim of the inner disc. An example of such a continuously engaged disc recliner is disclosed in U.S. Pat. No. 5,536,217.
It is common for continuously engaged recliners, as described above, to have play due to dimensional variation, clearances by design, or long term wear which result in a chucking motion of the seat back.
This invention relates to a continuously engaged recliner assembly for releaseably locking a seat back in one of a plurality of reclined positions relative to a seat cushion of a vehicle seat. The recliner assembly comprises a fixed flange having an annular rim of gear teeth and a mobile flange spaced apart from the fixed flange. An input shaft extends between and is journaled to both the fixed and mobile flanges to define a longitudinal pivot axis. At least two cam members are mounted to the input shaft. At least two pinion gears are operatively coupled to respective cam members and adapted for engagement with the annular rim of gear teeth on the fixed flange. Each of the pinion gears are driven by one of the cam members in hypocycloidal motion about the fixed flange during rotation of the input shaft relative to the fixed flange. Each of the pinion gears are operatively coupled to said mobile flange for transferring motion of the pinion gears to the mobile flange. A biasing member extends between the cam members for rotatably biasing apart the cam members about the pivot axis.
The engagement of the annular rim of gear teeth on the fixed flange with each of the pinion gears defines a first clearance between the annular rim of gear teeth on the fixed flange and each of the pinion gears. Each of the cam members includes a keyed bore for receiving the input shaft in splined relation therethrough. A second clearance is defined between the input shaft and each of the cam members such that the biasing member, acting upon the cam members, minimizes both of the first and second clearances.
The mobile flange includes an aperture and each of the pinion gears includes an aperture corresponding to the aperture of the mobile flange. A pin extends through the apertures of each of the pinion gears and the mobile flange for transferring motion of the pinion gears to the mobile flange.
The apertures of both of the pinion gears are oversized relative to the pin, so that the mobile flange is rotatably driven about the pivot axis in response to hypocycloidal motion of the pinion gears about the fixed flange.